The search for new antibiotics produced by soil microorganisms has encompassed the screening of various genera of bacteria, higher bacteria and fungi including many species within each genus and many strains within each species.
Among the microorganisms that have not received must attention are those that belong to the genus Pseudonocardia. This genus and the genus Nocardia belong to the Order Actinomycetales with the genus Pseudonocardia differentiated from Nocardia by the production in the aerial mycelium of long unbranched chains of spores by acropetal development and the zig-zag pattern of growth of some hypae.